Quality of Service (QoS) is a measure of telecommunications service quality provided by a carrier to a subscriber. In asynchronous transfer mode (ATM) networks, QoS may be defined on an end-to-end basis, e.g., in terms of how frequently packets are delivered intact and on time. Example ATM performance parameters used to calculate QoS include cell error ratio, cell loss ratio, cell transfer delay, and cell delay variability.
Carriers typically divide ATM network traffic into classes, each of which is guaranteed a minimum QoS. Subscribers usually pay for class allocations based on the type(s) of traffic they expect to send and receive via the network. For instance, subscribers who expect to send time-sensitive traffic, such as voice traffic, may choose to pay for a greater allocation of higher class service, i.e., service with a better guaranteed QoS. Unfortunately, it is often difficult to determine the traffic weight and traffic rate settings necessary for achieving the desired QoS. In the past, difficulties in determining the appropriate traffic weight and rate settings have led to lost revenue for service providers.